Determination of maximal oxygen consumption in exercising pregnant sheep

1992 ◽  
Vol 73 (1) ◽  
pp. 234-239 ◽  
Author(s):  
M. T. Jones ◽  
R. E. Rawson ◽  
D. Robertshaw
Keyword(s):  
Oxygen Consumption ◽  
Maximal Oxygen Consumption ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Flow Distribution ◽  
Pregnant Sheep ◽  
Flow Through ◽  
The Relationship ◽  
Exercise During Pregnancy

Previous work with pregnant ewes has shown that acute bouts of exercise may cause changes in plasma hormone concentrations, blood flow distribution, and maternal and fetal temperatures. However, most of these studies do not quantify the chosen exercise intensity through measurement of oxygen consumption (VO2). Therefore the purpose of this study was to statistically model the VO2 response of pregnant sheep to treadmill (TM) exercise to determine the exercise intensities (% maximal VO2) of previous studies. Ewes with either single (n = 9) or twin (n = 5) fetuses were studied from 100 to 130 days of gestation. After 1–2 wk of TM habituation, maximal VO2 (VO2max) was determined by measurements of VO2 (open flow-through method) and blood lactate concentration. VO2 was measured as a function of TM incline (0, 3, 5, and 7 degree) and speed (0.8–3.4 m/s). VO2max averaged 57 +/- 7 (SD) ml.min-1.kg-1, and peak lactate concentration during exercise averaged 22 +/- 2 mmol/l. The relationship between VO2 (ml.min-1.kg-1) and incline (INC) and speed (SP) [VO2 = 0.70(INC) + 13.95(SP) + 1.07(INC x SP) - 1.18] was linear (r2 = 0.94). Our findings suggest that most previous research used exercise intensities less than 60% VO2max and indicate the need for further research that examines the effect of exercise during pregnancy at levels greater than 60% VO2max.

scholarly journals Effects of a 2-km Swim on Markers of Cycling Performance in Elite Age-Group Triathletes

Sports ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 82
Author(s):  
Jeffrey Rothschild ◽  
George H. Crocker
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Blood Lactate ◽  
Peak Power ◽  
Maximal Oxygen Consumption ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Cycling Performance ◽  
Age Group

The purpose of this study was to examine the effects of a 2-km swim on markers of subsequent cycling performance in well-trained, age-group triathletes. Fifteen participants (10 males, five females, 38.3 ± 8.4 years) performed two progressive cycling tests between two and ten days apart, one of which was immediately following a 2-km swim (33.7 ± 4.1 min). Cycling power at 4-mM blood lactate concentration decreased after swimming by an average of 3.8% (p = 0.03, 95% CI −7.7, 0.2%), while heart rate during submaximal cycling (220 W for males, 150 W for females) increased by an average of 4.0% (p = 0.02, 95% CI 1.7, 9.7%), compared to cycling without prior swimming. Maximal oxygen consumption decreased by an average of 4.0% (p = 0.01, 95% CI −6.5, −1.4%), and peak power decreased by an average of 4.5% (p < 0.01, 95% CI −7.3, −2.3%) after swimming, compared to cycling without prior swimming. Results from this study suggest that markers of submaximal and maximal cycling are impaired following a 2-km swim.

scholarly journals Acute Physiological Responses to High-Intensity Resistance Circuit Training vs. Traditional Strength Training in Soccer Players

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 383
Author(s):  
Cristian Marín-Pagán ◽  
Anthony J. Blazevich ◽  
Linda H. Chung ◽  
Salvador Romero-Arenas ◽  
Tomás T. Freitas ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
High Intensity ◽  
Maximal Oxygen Consumption ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Soccer Players ◽  
Metabolic Responses ◽  
Post Exercise ◽  
Training Strategy ◽  
Training Protocols

The aim of this study was to evaluate and compare the cardiorespiratory and metabolic responses induced by high-intensity resistance circuit-based (HRC) and traditional strength (TS) training protocols. Ten amateur soccer players reported to the laboratory on four occasions: (1) protocol familiarization and load determination; (2) maximal oxygen consumption test; (3) and (4) resistance training protocols (HRC and TS), completed in a cross-over randomized order. In both protocols, the same structure was used (two blocks of 3 sets × 3 exercises, separated by a 5-min rest), with only the time between consecutive exercises differing: TS (3 min) and HRC (~35 s, allowing 3 min of local recovery). To test for between-protocol differences, paired t-tests were applied. Results showed that oxygen consumption and heart rate during HRC were 75% and 39% higher than TS, respectively (p < 0.001). After the training sessions, blood lactate concentration at 1.5, 5 and 7 min and excess post-exercise oxygen consumption were higher in HRC. The respiratory exchange ratio was 6.7% greater during HRC, with no between-group differences found post-exercise. The energy cost of HRC was ~66% higher than TS. In conclusion, HRC training induces greater cardiorespiratory and metabolic responses in soccer players and thus may be a time-effective training strategy.

The Respiration of Cancer Pagurus Under Normoxic and Hypoxic Conditions

1982 ◽  
Vol 97 (1) ◽  
pp. 273-288 ◽  
Author(s):  
S. M. BRADFORD ◽  
A. C. TAYLOR
Keyword(s):  
Oxygen Consumption ◽  
Energy Savings ◽  
Lactate Concentration ◽  
Oxygen Affinity ◽  
Cardiac Activity ◽  
Blood Lactate Concentration ◽  
Minor Role ◽  
Rhythmic Pattern ◽  
Cancer Pagurus ◽  
Wide Range

The respiration of Cancer pagurus under normoxic conditions and its respiratory responses to hypoxia are described. Respiration of quiescent crabs is characterized by a rhythmic pattern of ventilation and cardiac activity in which periods of apnoea and bradycardia of approximately 5 min duration alternate with longer periods of active ventilation and cardiac activity. The significance of this rhythmic ventilatory behaviour is discussed and evidence is presented to account for this behaviour in terms of allowing energy savings to be made during periods of inactivity. During a ventilatory pause the PO2 of the post-branchial blood falls from its normal level of 94 ± 5 torr to only 24 ± 3 torr. The blood of Cancer provides a store of oxygen which is used during pausing to maintain aerobic metabolism. Anaerobic metabolism does not appear to contribute significantly to energy production during these periods since no increase in the blood lactate concentration was recorded. Cancer haemocyanin has a high oxygen affinity (P50 = 5–10 torr) and exhibits a large, positive Bohr shift (Δ log P50/pH = −1.18). However, under normal conditions the pigment has only a minor role in supplying oxygen to the tissues, since over 91% is carried in solution. Cancer pagurus exhibits quite a high degree of respiratory independence and is able to maintain its rate of oxygen consumption approximately constant over a wide range of ambient oxygen tension, down to a PO2 of 60–80 torr, below which it declines. Similarly there was little change in heart rate during hypoxia until a PO2 of 20–40 torr was reached below which it also declined sharply. Oxygen consumption during hypoxia was maintained primarily as a result of an increase in ventilation volume and oxygen extraction. During hypoxia the PO2 of both the pre- and post-branchial blood declined and resulted in a reduction in the PO2 gradient across the respiratory surface (ΔPO2). Oxygen uptake during hypoxia was facilitated, however, by an increase in the transfer factor (TO2).

scholarly journals Use of the Accusport semi-automated analyser to determine blood lactate as an aid in the clinical assessment of horses with colic

2001 ◽  
Vol 72 (1) ◽  
Author(s):  
M.L. Schulman ◽  
J.P. Nurton ◽  
A.J. Guthrie
Keyword(s):  
Blood Lactate ◽  
Laboratory Data ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Tissue Perfusion ◽  
Diagnostic Methods ◽  
Initial Assessment ◽  
Clinically Normal ◽  
Case Outcome

The most useful diagnostic methods in the initial evaluation of horses with colic assess the morphological and functional status of the gastrointestinal tract and cardiovascular status. This evaluation is best achieved using a combination of clinical and laboratory data. Blood lactate concentration (BL) is one of these variables. BL rises mainly due to poor tissue perfusion and anaerobic glycolysis associated with shock, providing an indicator of both the severity of disease and its prognosis. A hand-held lactate meter, Accusport, provides a rapid (60 seconds), inexpensive dry-chemical-based determination of BL. This trial evaluated the Accusport's ability to provide BL data as an adjunct to the initial clinical evaluation of horses with colic. The accuracy of the Accusport was tested by evaluation of its interchangeability with the benchmark enzymatic kit evaluation of BL in a trial using data collected firstly from 10 clinically normal control horses and subsequently from 48 horses presented with signs of colic. The BL values were recorded together with the clinical variables of heart rate (HR), capillary refill time (CRT), haematocrit (Hct), and pain character and severity on the initial assessment of the colic horses. Information regarding choice of therapeutic management (medical or surgical) and eventual case outcome (full recovery or died/euthanased) was recorded. The Accusport was found to be interchangeable with the enzymatic kit for recording BL values in colic horses with BL <10 mmol/ , which is within the BL range associated with survival. The interchangeability of an additional, laboratory-based wet chemical assay for BL, the Stat 7 was simultaneously evaluated for the colic and control horses. The Stat 7 was found to be interchangeable with the enzymatic kit for BL determination of colic horses. No linear associations between BL values with HR, CRT, Hct or pain assessment were observed. No relationship with either selection of therapeutic method or eventual case outcome was observed. All horses with BL >8 mmol/ died or were euthanased.

Acute anemia increases lactate production and decreases clearance during exercise

1989 ◽  
Vol 67 (2) ◽  
pp. 756-764 ◽  
Author(s):  
S. G. Gregg ◽  
R. S. Mazzeo ◽  
T. F. Budinger ◽  
G. A. Brooks
Keyword(s):  
Blood Glucose ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Flow Distribution ◽  
Plasma Catecholamine ◽  
Metabolic Clearance ◽  
Sprague Dawley ◽  
Mean Values

We evaluated whether elevated blood lactate concentration during exercise in anemia is the result of elevated production or reduced clearance. Female Sprague-Dawley rats were made acutely anemic by exchange transfusion of plasma for whole blood. Hemoglobin and hematocrit were reduced 33%, to 8.6 +/- 0.4 mg/dl and 26.5 +/- 1.1%, respectively. Blood lactate kinetics were studied by primed continuous infusion of [U-14C]lactate. Blood flow distribution during rest and exercise was determined from injection of 153Gd- and 113Sn-labeled microspheres. Resting blood glucose (5.1 +/- 0.2 mM) and lactate (1.9 +/- 0.02 mM) concentrations were not different in anemic animals. However, during exercise blood glucose was lower in anemic animals (4.0 +/- 0.2 vs. 4.6 +/- 0.1 mM) and lactate was higher (6.1 +/- 0.4 vs. 2.3 +/- 0.5 mM). Blood lactate disposal rates (turnover measured with recyclable tracer, Ri) were not different at rest and averaged 136 +/- 5.8 mumol.kg-1.min-1. Ri was significantly elevated in both control (260.9 +/- 7.1 mumol.kg-1.min-1) and anemic animals (372.6 +/- 8.6) during exercise. Metabolic clearance rate (MCR = Ri/[lactate]) did not differ during rest (151 +/- 8.2 ml.kg-1.min-1); MCR was reduced more by exercise in anemic animals (64.3 +/- 3.8) than in controls (129.2 +/- 4.1). Plasma catecholamine levels were not different in resting rats, with pooled mean values of 0.45 +/- 0.1 and 0.48 +/- 0.1 ng/ml for epinephrine (E) and norepinephrine (NE), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Disposal of blood [1-13C]lactate in humans during rest and exercise

1986 ◽  
Vol 60 (1) ◽  
pp. 232-241 ◽  
Author(s):  
R. S. Mazzeo ◽  
G. A. Brooks ◽  
D. A. Schoeller ◽  
T. F. Budinger
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Curvilinear Relationship ◽  
O2 Consumption ◽  
Lactate Oxidation ◽  
Respiratory Parameters ◽  
Steady Rate ◽  
Lactate Levels

Lactate irreversible disposal (RiLa) and oxidation (RoxLa) rates were studied in six male subjects during rest (Re), easy exercise [EE, 140 min of cycling at 50% of maximum O2 consumption (VO2max)] and hard exercise (HE, 65 min at 75% VO2max). Twenty minutes into each condition, subjects received a Na+-L(+)-[1–13C]lactate intravenous bolus injection. Blood was sampled intermittently from the contralateral arm for metabolite levels, acid-base status, and enrichment of 13C in lactate. Expired air was monitored continuously for determination of respiratory parameters, and aliquots were collected for determination of 13C enrichment in CO2. Steady-rate values for O2 consumption (VO2) were 0.33 +/- 0.01, 2.11 +/- 0.03, and 3.10 +/- 0.03 l/min for Re, EE, and HE, respectively. Corresponding values of blood lactate levels were 0.84 +/- 0.01, 1.33 +/- 0.05, and 4.75 +/- 0.28 mM in the three conditions. Blood lactate disposal rates were significantly correlated to VO2 (r = 0.78), averaging 123.4 +/- 20.7, 245.5 +/- 40.3, and 316.2 +/- 53.7 mg X kg-1 X h-1 during Re, EE, and HE, respectively. Lactate oxidation rate was also linearly related to VO2 (r = 0.81), and the percentage of RiLa oxidized increased from 49.3% at rest to 87.0% during exercise. A curvilinear relationship was found between RiLa and blood lactate concentration. It was concluded that, in humans, 1) lactate disposal (turnover) rate is directly related to the metabolic rate, 2) oxidation is the major fate of lactate removal during exercise, and 3) blood lactate concentration is not an accurate indicator of lactate disposal and oxidation.

scholarly journals The perforation of the frustules of planktonic diatoms Pseudosolenia calcar-avis and Proboscia alata (Bacillariophyceae)

2019 ◽  
Vol 2 ◽  
pp. 19-26
Author(s):  
Lyakh A.M.
Keyword(s):  
Surface Area ◽  
Geometric Modeling ◽  
Direct Determination ◽  
Entire Surface ◽  
Planktonic Diatoms ◽  
Centric Diatoms ◽  
Flow Through ◽  
Material Energy ◽  
The Relationship

Physiological and biophysical characteristics of microalgae should strongly depend on the surface area of the cover of organisms, as all the material-energy streams flow through the surface. However, to determine the relationship between the intensity of the flow of substances with the physiology of unicellular, it is necessary to take into account only the area of perforations, since the rest of the shell is impermeable for substances. The direct determination of the area of perforations on the entire surface of the microalgae is very difficult. Therefore, the indirect method of estimating the perforation area using geometric modeling of the perforation distribution (texture) on the surface was used in this study. The object of the research is two types of marine plankton diatoms with large cylindrical frustules. It was assumed that the frustules are covered with a regular triangular texture of the areola. This texture can be divided into regular hexagons, which allows us to estimate the number of areolas as the ratio of the surface area of the frustules to the area of one hexagon. The model takes into account that each areola is covered with a silicon plate perforated by a smaller pore. The multiplication of the number of areolas on the area of a given pore gives the value of the total area of perforations. Calculations showed that the perforation of the frustules of Proboscia alata was 4%, and Pseudosolenia calcar-avis – 6%. These are the first estimates of the perforation of the entire surface of the diatom frustules. The acquired data confirms the hypothesis that frustules of the most centric diatoms are covered by pores by about 5%, and the other surface is impervious to material flows.

RELATIONSHIP BETWEEN THE LEVEL OF EDUCATION AND FUNCTIONAL CAPACITY IN ACTIVE ELDERLY ADULTS

2014 ◽  
pp. 1-5
Author(s):  
M.-M. DUBUC ◽  
S. BARBAT-ARTIGAS ◽  
A.D. KARELIS ◽  
M. AUBERTIN-LEHEUDRE
Keyword(s):  
Oxygen Consumption ◽  
Functional Capacity ◽  
Maximal Oxygen Consumption ◽  
The Elderly ◽  
Knee Extensors ◽  
Elderly Adults ◽  
Timed Up And Go ◽  
Level Of Education ◽  
Sf 36 ◽  
The Relationship

Background:Both the level of education and functional capacity seems to be associated with the levelof physical activity in the elderly. However, the relationship between the level of education and functionalcapacity in active elderly adults is poorly understood. Objective:To examine the association between the level ofeducation and the functional capacity profile of active elderly adults. Design:Cross-sectional. Participants:Onehundred and four elderly men and 198 postmenauposal women (mean age: 62.7 ± 7.6 years old) were recruitedamong registered members of the YMCAs of Montreal who practiced at least one hour of structured physicalactivity per week. Participants were then divided in two groups based on their level of education (the cut-offpoint was the high-school diploma). Measurements:Body composition (DXA), muscle strength (knee extensors,handgrip), estimated maximal oxygen consumption (2-km walk test), perceived health (SF-36) and functionalcapacity (timed up and go, alternate step and one-leg stance tests) were measured. The level of education of theparticipants was assessed by questionnaire. Results:Body composition was similar between groups. We observedthat all functional capacity tests as well as the global functional capacity score were significantly higher in themost educated group compared to the least educated group (p<0.05). In addition, the most educated group hadsignificantly higher levels of knee extensors strength, estimated maximal oxygen consumption and perception ofphysical functioning. Conclusions:A higher level of education was associated with a favourable functionalcapacity profile in our cohort of active elderly adults. However, the mechanism(s) which could mediate thisassociation remain(s) unknown.

Increased clearance of lactate after short-term training in men

1995 ◽  
Vol 79 (6) ◽  
pp. 1862-1869 ◽  
Author(s):  
S. M. Phillips ◽  
H. J. Green ◽  
M. A. Tarnopolsky ◽  
S. M. Grant
Keyword(s):  
Blood Lactate ◽  
Clearance Rate ◽  
Maximal Oxygen Consumption ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Constant Infusion ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Short Term ◽  
Mitochondrial Potential

A short-term training model previously shown to result in a tighter metabolic control in working muscle in the absence of an increase in mitochondrial potential was used to examine changes in lactate turnover. Lactate flux was studied before and after 10 days of cycle training [2 h/day at 59% maximal oxygen consumption (VO2max)] in untrained men [VO2max = 45.5 +/- 2.4 (SE) ml.kg-1.min-1). A primed constant infusion of L-[1–13C]lactate was used to examine lactate kinetics during a prolonged exercise protocol (90 min at 59% VO2max). Rate of appearance of lactate increased with exercise (P < 0.01), both pretraining (rest = 30.3 +/- 4.9 ml.kg-1.min-1, exercise = 115 +/- 14 ml.kg-1.min-1) and posttraining (rest = 28.4 +/- 4.7 ml.kg-1.min-1, exercise = 112 +/- 13 ml.kg-1.min-1). Despite a lower blood lactate concentration (P < 0.05) during exercise after training, there was no difference in the rate of appearance of lactate. Training increased (P < 0.05) the metabolic clearance rate of lactate during exercise from 36.8 +/- 4.8 to 51.4 +/- 6.8 ml.kg-1.min-1. These findings indicate that at least part of the lower exercising blood lactate observed after training is due to an increase in metabolic clearance rate. In addition, the lower intramuscular lactate levels suggest a decreased recruitment of glycolysis particularly early in exercise.

scholarly journals Prolonged static stretching causes acute, nonmetabolic fatigue and impairs exercise tolerance during severe-intensity cycling

2020 ◽  
Vol 45 (8) ◽  
pp. 902-910
Author(s):  
Alessandro L. Colosio ◽  
Massimo Teso ◽  
Silvia Pogliaghi
Keyword(s):  
Oxygen Consumption ◽  
Exercise Tolerance ◽  
Muscle Activation ◽  
Metabolic Response ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Time To Exhaustion ◽  
Static Stretching ◽  
Perception Of Effort ◽  
Severe Intensity

We tested the hypothesis that static stretching, an acute, nonmetabolic fatiguing intervention, reduces exercise tolerance by increasing muscle activation and affecting muscle bioenergetics during cycling in the “severe” intensity domain. Ten active men (age, 24 ± 2 years; body mass, 74 ± 11 kg; height, 176 ± 8 cm) participated in identical constant-load cycling tests of equal intensity, of which 2 tests were carried out under control conditions and 2 were done after stretching. This resulted in a 5% reduction of maximal isokinetic sprinting power output. We measured (i) oxygen consumption, (ii) electromyography, (iii) deoxyhemoglobin, (iv) blood lactate concentration; (v) time to exhaustion, and (vi) perception of effort. Finally, oxygen consumption and deoxyhemoglobin kinetics were determined. Force reduction following stretching was accompanied by augmented muscle excitation at a given workload (p = 0.025) and a significant reduction in time to exhaustion (p = 0.002). The time to peak oxygen consumption was reduced by stretching (p = 0.034), suggesting an influence of the increased muscle excitation on the oxygen consumption kinetics. Moreover, stretching was associated with a mismatch between O2 delivery and utilization during the isokinetic exercise, increased perception of effort, and blood lactate concentration; these observations are all consistent with an increased contribution of the glycolytic energy system to sustain the same absolute intensity. These results suggest a link between exercise intolerance and the decreased ability to produce force. Novelty We provided the first characterization of the effects of prolonged stretching on the metabolic response during severe cycling. Stretching reduced maximal force and augmented muscle activation, which in turn increased the metabolic response to sustain exercise.

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